I'm making a virtual computer with a custom font and programming environment (Mini Micro), all Unicode based. I have need for a few custom glyphs in my environment. I know about the Private Use Areas, but I'm wondering about the "control" code points at U+0080 through U+009F. I can't find any documentation on what these points are for beyond "control".
Would it be a gross abuse of Unicode to tuck a few of my custom glyphs in there? What would be a proper use of them?
Wikipedia lists their meaning. You get 2 of them for your use, U+0091 and U+0092.
The 0x80 - 0x9F range you referto to is generally called the C1 control characters. Like other control codes, the C1s are for code extension, and by their very nature, some are generally left open for further expansion and thus have only vague standardization.
The original and most comprehensive reference is probably ECMA-48 - up to the Fifth Edition in June 1991. (The link takes you to a free download in PDF format.)
For additional glyphs, C1 codes would not be appropriate. In effect, the whole idea of control codes is that they are the special case of non-graphical codes.
UNICODE has continued to evolve, with an emoji block that has a lot of "characters" you might not expect. Let's try one: 💎 it is officially called the GemStone Emoji. I used this copy/paste website to insert it, you might look to see if something you can use has been standardized in the Emoji code block.
One of the interesting things about the emoji characters is that they are double-wide, even in a fixed-width font.
Microsoft uses them for smart quotes the Euro and a few other symbols in its latin-1 extension cp1252. As this character encoding is frequently reported as latin-1 using these code points for other uses can cause problems, especially as latin-1 is supposed to be code point equivalent to Unicode. This Wikipedia page gives some history and the meanings of these control characters.
Related
Pretty much as the title says. Rendering all of the unicode format correctly what with composite characters and characters that affect other characters and ligatures is really hard, I understand that. We have fonts that seem to be designed for maximum Unicode symbol support(Symbola, Code2001, others) and specialized fonts for certain planes or character ranges(BabelStone Han, others).
I don't know much about the underlying technical details for fonts. Is there a maximum size? Is it a copyright problem? Is essentially redrawing all ~110,000 extant glyphs too hard? I understand style concerns, but why not fall back to a 'default' font that had glyphs for everything? They're on unicode.org, redrawing them all would be pretty hard work but then you'd have a guaranteed fallback font for everything. If you got rights to some pre-existing fonts you could just composite them and that should help a lot. Such a font would be a great help to humanity and I can't see a good technical reason why it doesn't exist or at least an open-source effort to create it, so I presume an invisible-to-me reason why it can't be done.
What is that reason?
"Why would you even want that?" questions aside, from a programming perspective there's a very simple reason: the OpenType spec only affords an addressable glyph index space of one USHORT, so one font can only support 16 bits worth of glyphs identifiers, or 65,536 glyphs max. (And note the terminology: a "glyph" is not the same as a "character" or "letter")
The current version of Unicode, v8 as of this answer, contains 120,737 assigned code points, or almost twice as many as fit in a modern font (2021 edit: v13 upped this number to 143,859). In fact, Unicode hasn't been able to fit in a modern OpenType font since 2001, with the release of Unicode 3.1, which upped the number of code points from 49,259 to 94,205.
"So what about font collections?" I hear you ask. Why not use multiple fonts and support all unicode that way? Well now, you've just described Adobe's Sans Pro, and Google's Noto (which are the same font).
As for the "how hard can it be": a uniform style for all glyphs in Unicode, across 129 established written scripts on this planet, each with their own typesetting rules? Incredibly hard. You may think fonts are just files with pictures for letters, and someone types a letter, that picture shows up: that is not how fonts work, and isn't how fonts have worked since the late 1980's.
Modern fonts are the typographic equivalent of a game ROM: sure, it's not much use without the hardware or software to run that ROM on, but all the things that actually matter are in the ROM. Similarly, modern fonts contain all the information for typesetting. Not just pictures, they contain the metadata, the metrics, the positioning and substitutions rules for arbitrary sequences, with separate rule sets for each written script that OpenType supports, mandatory and optional ligatures, language-specific character replacements for letters at the start/middle/final position in a word, or in isolation, character repositioning relative to arbitarily complex sequences of other characters either before or after it, arbitrarily complex sequence replacements with other arbitrarily complex sequences, possible bitmap fallbacks for small-point rendering, hinting instructions on how to properly rasterize vector graphics that are inherently not aligned to any particular pixel grid, and more. A modern font is a ridiculously complex application, that a font engine consults to figure out how to typeset sequences of code points.
Making a (set of) Unicode-encompassing font(s) that looks good for all contexts is a vast team effort.
So: "Why isn't there a font that contains all Unicode glyphs?", because that's been technically impossible since 2001. We can, and do, make font families that cover all of Unicode, but with 129 different scripts all with their own typesetting rules, it's a lot of work, and almost (almost) not worth the effort compared to only covering a subset of all languages.
And as for this:
Such a font would be a great help to humanity and I can't see a good technical reason why it doesn't exist or at least an open-source effort to create it, so I presume an invisible-to-me reason why it can't be done.
Just because you didn't know about them, doesn't mean they don't exist, with millions of people who are familiar with them. They exist =)
They're even open source, go out and thank the people who made them!
There is GNU Unifont. It aims to contain all Unicode, except Apple Emoji.
You will probably find what you are looking for at the following links.
Unicode Character Table
HTML Character Entity References
Huge List of Unicode Symbols
List of Unicode Characters of Category “Other Symbol
This other is funny for particular character since you can draw what you search:
Unicode Character Recognition
Can't enter unicode character with Alt+ even with EnableHexNumpad
Basic Questions
Q: How many characters are in Unicode?
A: The short answer is that as of Version 13.0, the Unicode Standard contains 143,859 characters. The long answer is rather more complicated, because of all the different kinds of characters that people might be interested in counting.
Unicode font
A Unicode font is a computer font that maps glyphs to code points defined in the Unicode Standard. The vast majority of modern computer fonts use Unicode mappings, even those fonts which only include glyphs for a single writing system, or even only support the basic Latin alphabet.
Fonts which support a wide range of Unicode scripts and Unicode symbols are sometimes referred to as "pan-Unicode fonts", although as the maximum number of glyphs that can be defined in a TrueType font is restricted to 65,535, it is not possible for a single font to provide individual glyphs for all defined Unicode characters (143,859 characters, with Unicode 13.0).
...
No single "Unicode font" includes all the characters defined in the present revision of ISO 10646 (Unicode) standard, as more and more languages and characters are continually added to it, and common font formats cannot contain more than 65,535 glyphs (about half the number of characters encoded in Unicode).
As a result, font developers and foundries incorporate new characters in newer versions or revisions of a font, or in separate auxiliary fonts intended specifically for particular languages.
Enjoy!
I have a dataset which mixes use of unicode characters \u0421, 'С' and \u0043, 'C'. Is there some sort of unicode comparison which considers those two characters the same? So far I've tried several ICU collations, including the Russian one.
There is no Unicode comparison that treats characters as the same on the basis of visual identity of glyphs. However, Unicode Technical Standard #39, Unicode Security Mechanisms, deals with “confusables” – characters that may be confused with each other due to visual identity or similarity. It includes a data file of confusables as well as “intentionally confusable” pairs, i.e. “characters whose glyphs in any particular typeface would probably be designed to be identical in shape when using a harmonized typeface design”, which mainly consists of pairs of Latin and Cyrillic or Greek letters, like C and С. You would probably need to code your own use of this data, as ICU does not seem to have anything related to the confusable concept.
when you take a look at http://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt, you will see that some code positions are annotated for codepoints that are similar in use; however, i'm not aware of any extensive list that covers visual similarities across scripts. you might want to search for URL spoofing using intentional misspellings, which was discussed when they came up with punycode. other than that, your best bet might be to search the data for characters outside the expected using regular expressions, and compile a series of ad-hoc text fixers like text = text.replace /с/, 'c'.
I am trying to understand this stuff so that I can effectively work on internationalizing a project at work. I have just started and very much like to know from your expertise whether I've understood these concepts correct. So far here is the dumbed down version(for my understanding) of what I've gathered from web:
Character Encodings -> Set of rules that tell the OS how to store characters. Eg., ISO8859-1,MSWIN1252,UTF-8,UCS-2,UTF-16. These rules are also called Code Pages/Character Sets which maps individual characters to numbers. Apparently unicode handles this a bit differently than others. ie., instead of a direct mapping from a number(code point) to a glyph, it maps the code point to an abstract "character" which might be represented by different glyphs.[ http://www.joelonsoftware.com/articles/Unicode.html ]
Fonts -> These are implementation of character encodings. They are files of different formats (True Type,Open Type,Post Script) that contain mapping for each character in an encoding to number.
Glyphs -> These are visual representation of characters stored in the font files.
And based on the above understanding I have the below questions,
1)For the OS to understand an encoding, should it be installed separately?. Or installing a font that supports an encoding would suffice?. Is it okay to use the analogy of a protocol say TCP used in a network to an encoding as it is just a set of rules. (which ofcourse begs the question, how does the OS understands these network protocols when I do not install them :-p)
2)Will a font always have the complete implementation of a code page or just part of it?. Is there a tool that I can use to see each character in a font(.TTF file?)[Windows font viewer shows how a style of the font looks like but doesn't give information regarding the list of characters in the font file]
3)Does a font file support multiple encodings?. Is there a way to know which encoding(s) a font supports?
I apologize for asking too many questions, but I had these in my mind for some time and I couldn't find any site that is simple enough for my understanding. Any help/links for understanding this stuff would be most welcome. Thanks in advance.
If you want to learn more, of course I can point you to some resources:
Unicode, writing systems, etc.
The best source of information would probably be this book by Jukka:
Unicode Explained
If you were to follow the link, you'd also find these books:
CJKV Information Processing - deals with Chinese, Japanese, Korean and Vietnamese in detail but to me it seems quite hard to read.
Fonts & Encodings - personally I haven't read this book, so I can't tell you if it is good or not. Seems to be on topic.
Internationalization
If you want to learn about i18n, I can mention countless resources. But let's start with book that will save you great deal of time (you won't become i18n expert overnight, you know):
Developing International Software - it might be 8 years old but this is still worth every cent you're going to spend on it. Maybe the programming examples regard to Windows (C++ and .Net) but the i18n and L10n knowledge is really there. A colleague of mine said once that it saved him about 2 years of learning. As far as I can tell, he wasn't overstating.
You might be interested in some blogs or web sites on the topic:
Sorting it all out - Michael Kaplan's blog, often on i18n support on Windows platform
Global by design - John Yunker is actively posting bits of i18n knowledge to this site
Internationalization (I18n), Localization (L10n), Standards, and Amusements - also known as i18nguy, the web site where you can find more links, tutorials and stuff.
Java Internationalization
I am afraid that I am not aware of many up to date resources on that topic (that is publicly available ones). The only current resource I know is Java Internationalization trail. Unfortunately, it is fairly incomplete.
JavaScript Internationalization
If you are developing web applications, you probably need also something related to i18n in js. Unfortunately, the support is rather poor but there are few libraries which help dealing with the problem. The most notable examples would be Dojo Toolkit and Globalize.
The prior is a bit heavy, although supports many aspects of i18n, the latter is lightweight but unfortunately many stuff is missing. If you choose to use Globalize, you might be interested in the latest Jukka's book:
Going Global with JavaScript & Globalize.js - I read this and as far I can tell, it is great. It doesn't cover the topics you were originally asking for but it is still worth reading, even for hands-on examples of how to use Globalize.
Apparently unicode handles this a bit differently than others. ie.,
instead of a direct mapping from a number(code point) to a glyph, it
maps the code point to an abstract "character" which might be
represented by different glyphs.
In the Unicode Character Encoding Model, there are 4 levels:
Abstract Character Repertoire (ACR) — The set of characters to be encoded.
Coded Character Set (CCS) — A one-to-one mapping from characters to integer code points.
Character Encoding Form (CEF) — A mapping from code points to a sequence of fixed-width code units.
Character Encoding Scheme (CES) — A mapping from code units to a serialized sequence of bytes.
For example, the character 𝄞 is represented by the code point U+1D11E in the Unicode CCS, the two code units D834 DD1E in the UTF-16 CEF, and the four bytes 34 D8 1E DD in the UTF-16LE CES.
In most older encodings like US-ASCII, the CEF and CES are trivial: Each character is directly represented by a single byte representing its ASCII code.
1) For the OS to understand an encoding, should it be installed
separately?.
The OS doesn't have to understand an encoding. You're perfectly free to use a third-party encoding library like ICU or GNU libiconv to convert between your encoding and the OS's native encoding, at the application level.
2)Will a font always have the complete implementation of a code page or just part of it?.
In the days of 7-bit (128-character) and 8-bit (256-character) encodings, it was common for fonts to include glyphs for the entire code page. It is not common today for fonts to include all 100,000+ assigned characters in Unicode.
I'll provide you with short answers to your questions.
It's generally not the OS that supports an encoding but the applications. Encodings are used to convert a stream of bytes to lists of characters. For example, in C# reading a UTF-8 string will automatically make it UTF-16 if you tell it to treat it as a string.
No matter what encoding you use, C# will simply use UTF-16 internally and when you want to, for example, print a string from a foreign encoding, it will convert it to UTF-16 first, then look up the corresponding characters in the character tables (fonts) and shows the glyphs.
I don't recall ever seeing a complete font. I don't have much experience with working with fonts either, so I cannot give you an answer for this one.
The answer to this one is in #1, but a short summary: fonts are usually encoding-independent, meaning that as long as the system can convert the input encoding to the font encoding you'll be fine.
Bonus answer: On "how does the OS understand network protocols it doesn't know?": again it's not the OS that handles them but the application. As long as the OS knows where to redirect the traffic (which application) it really doesn't need to care about the protocol. Low-level protocols usually do have to be installed, to allow the OS to know where to send the data.
This answer is based on my understanding of encodings, which may be wrong. Do correct me if that's the case!
i want to use korean translations under in my - quite large - wxwidgets application. The application uses the wxwidgets translation framework, which is based on gettext.
I have working translations for french, german and russian. I want to go unicode anyway, but my first question is:
does my application need unicode support to display korean and japanese languages?
If so, - just for interest - why does russian work without, since they have a cyrillic letterset?
I have thousands of string literals. Do i have to prepend each and every one of them with 'L' ? ( wxString foo("foo") --> wxString foo(L"foo") )
if so, did someone build a regex or sed or perl script to do this in ca. 500 .cpp files ? ( pleeze! =) )
Will this change in wxWidgets 3.0?
Unicode question general: i use these string literals in many descriptive and many technical ways .. as displayed text as well as parts of GLSL shaders as well as XML. These APIs have char* / const char* as function arguments, so my internal wxString representation should not matter in these areas. Theory and practice: is this true? Some experiences to share, anyone?
I do some text processing ( comparing, string finding etc ) - are there any logical differences in unicode vs. ansi?
Is there any remarkeable performance impact in using Unicode?
Thank you!
Wendy
Addressing some of your questions…
does my application need unicode support to display korean and japanese languages?
If so, - just for interest - why does russian work without, since they have a cyrillic letterset?
Russian fits in a single-byte charset, just like western European languages (though it is a different charset). Korean and Japanese (and Chinese) don't. There are many workarounds for this, but the most elegant I know of to date is to use Unicode so that you don't need to rebuild your application for each locale; just change its message catalog.
Unicode question general: i use these string literals in many descriptive and many technical ways .. as displayed text as well as parts of GLSL shaders as well as XML. These APIs have char* / const char* as function arguments, so my internal wxString representation should not matter in these areas. Theory and practice: is this true? Some experiences to share, anyone?
Only strings that are going to be shown to (non-technical) users need to be localized, so they're the only ones that have to be in Unicode. The most common approach is to use UTF-8 (which is a particular way of encoding Unicode) as that means that ASCII strings – the most common type passed around inside programs – are exactly the same, which simplifies things a lot. The down-side is that you no longer have cheap indexing into the string as not all characters are the same number of bytes long. That can be anything from a non-issue to a right royal hindering PITA, depending on what the program is doing.
I do some text processing ( comparing, string finding etc ) - are there any logical differences in unicode vs. ansi?
Comparisons work fine, as does simple string finding. Other operations (e.g., getting the 20th character of a string, or working out how many characters into a string you've found a substring) are nasty because you've not got constant character widths. The nastiness can be mitigated by using wide characters, but they're less nice to use for external data (they introduce potential problems with endianness unless you go into working with byte-order marks, and that's another matter right there).
Is there any remarkeable performance impact in using Unicode?
Depends on exactly what you do. With UTF-8, if you're mostly dealing with ASCII text in reality then you get very little in the way of performance problems for most operations. With wide characters, you take more memory for every character, which naturally has performance implications (but which might acceptable because it does mean you've got constant-time indexing).
There's a korean .po file on http://www.wxwidgets.org/about/i18n.php for wxWidget's own strings. If your application displays wxWidget's own strings correctly when using that file, then it does not need Unicode support to display Korean and Japanese languages.
ISO-8859-5 is an 8 bit character set with Cyrillic letters.
Only if 1. does not yield the correct result. But if you want to translate the string, you should have used _().
I don't know.
wxWidgets 3.0 will not have separate Unicode- and ANSI-builds. 2.9.1 doesn't have, either.
It depends on how you use the arguments. C- and C++-functions usually operate on the representation of strings and are unaware of any particular character encoding. Particularly what you perceive to be a character and what the program considers a character might be different things.
See 6.
I do not know, but many toolkits use UTF-16 or UTF-32 instead of UTF-8 because these schemes are simpler. It's a size-speed tradeoff.
1.does my application need unicode support to display korean and japanese
languages?
Thanks to Oswald, i found out that you can have a korean translation without using unicode in your wxwidgets application. Change ( under windows, at least ) settings for non-unicode aware programs. But i still have to check out if this is enough for a whole application.
3.I have thousands of string literals. Do i have to prepend each
and every one of them with 'L' ? (
wxString foo("foo") --> wxString
foo(L"foo") )
If you have to use unicode with wxwidgets prior to 3.0, you have to. But do not use 'L' under wxwidgets, use wxT("foo")
4.if so, did someone build a regex or sed or perl script to do this in ca. 500 .cpp files ?
I did, at least a search and replace under Visual Studio:
Search: {"([^"]*)"}
Replace: wxT(\1)
But be careful! Will replace all string literals, #include "file.h" with #include wxT("file.h")
Will this change in wxWidgets 3.0?
Yes. See answer/quote above.
These days, more languages are using unicode, which is a good thing. But it also presents a danger. In the past there where troubles distinguising between 1 and l and 0 and O. But now we have a complete new range of similar characters.
For example:
ì, î, ï, ı, ι, ί, ׀ ,أ ,آ, ỉ, ﺃ
With these, it is not that difficult to create some very hard to find bugs.
At my work, we have decided to stay with the ANSI characters for identifiers. Is there anybody out there using unicode identifiers and what are the experiences?
Besides the similar character bugs you mention and the technical issues that might arise when using different editors (w/BOM, wo/BOM, different encodings in the same file by copy pasting which is only a problem when there are actually characters that cannot be encoded in ASCII and so on), I find that it's not worth using Unicode characters in identifiers. English has become the lingua franca of development and you should stick to it while writing code.
This I find particularly true for code that may be seen anywhere in the world by any developer (open source, or code that is sold along with the product).
My experience with using unicode in C# source files was disastrous, even though it was Japanese (so there was nothing to confuse with an "i"). Source Safe doesn't like unicode, and when you find yourself manually fixing corrupted source files in Word you know something isn't right.
I think your ANSI-only policy is excellent. I can't really see any reason why that would not be viable (as long as most of your developers are English, and even if they're not the world is used to the ANSI character set).
I think it is not a good idea to use the entire ANSI character set for identifiers. No matter which ANSI code page you're working in, your ANSI code page includes characters that some other ANSI code pages don't include. So I recommend sticking to ASCII, no character codes higher than 127.
In experiments I have used a wider range of ANSI characters than just ASCII, even in identifiers. Some compilers accepted it. Some IDEs needed options to be set for fonts that could display the characters. But I don't recommend it for practical use.
Now on to the difference between ANSI code pages and Unicode.
In experiments I have stored source files in Unicode and used Unicode characters in identifiers. Some compilers accepted it. But I still don't recommend it for practical use.
Sometimes I have stored source files in Unicode and used escape sequences in some strings to represent Unicode character values. This is an important practice and I recommend it highly. I especially had to do this when other programmers used ANSI characters in their strings, and their ANSI code pages were different from other ANSI code pages, so the strings were corrupted and caused compilation errors or defective results. The way to solve this is to use Unicode escape sequences.
I would also recommend using ascii for identifiers. Comments can stay in a non-english language if the editor/ide/compiler etc. are all locale aware and set up to use the same encoding.
Additionally, some case insensitive languages change the identifiers to lowercase before using, and that causes problems if active system locale is Turkish or Azerbaijani . see here for more info about Turkish locale problem. I know that PHP does this, and it has a long standing bug.
This problem is also present in any software that compares strings using Turkish locales, not only the language implementations themselves, just to point out. It causes many headaches
It depends on the language you're using. In Python, for example, is easierfor me to stick to unicode, as my aplications needs to work in several languages. So when I get a file from someone (something) that I don't know, I assume Latin-1 and translate to Unicode.
Works for me, as I'm in latin-america.
Actually, once everithing is ironed out, the whole thing becomes a smooth ride.
Of course, this depends on the language of choice.
I haven't ever used unicode for identifier names. But what comes to my mind is that Python allows unicode identifiers in version 3: PEP 3131.
Another language that makes extensive use of unicode is Fortress.
Even if you decide not to use unicode the problem resurfaces when you use a library that does. So you have to live with it to a certain extend.